With the BlackVue you can select automatic mode which means you can essentially forget about the camera and it'll do it's job. The BlackVue has G sensors in it so once you start moving it'll start to record. As part of the automatic mode you can also use park mode which essentially senses movement in front of the car while it's park, turns itself on and records it.

2. The GoPro doesn't loop records

I think the GoPro records in about 30 min segments and once the memory is full it stops recording. The BlackVue records on a loop 1, 2, 5 minutes etc... The software that comes with the camera plays these seamlessly. Once the memory card is full it'll automatically start to delete oldest files unless something untoward was noticed in the file (i.e. higher than normal g force such as an accident).

In terms of quality I think the GoPro and BlackVue are quite similar.

For paintballing a GoPro is going to win hands down but as a dash cam for track days and normal use the BlackVue wins IMO.

The GoPro is bulkier than the BlackVue and isn't going to look great on you dash. Having seen the BlackVue installed it's almost invisible, just kind of blends in.